Background — SwRI has performed mine blast testing for a
variety of clients over the past several years to support the development of
mine blast-resistant vehicles. Tests have been performed on full-scale vehicles
and on vehicle components. A majority of component tests have been performed on
the SwRI Universal Landmine Test System (ULTS), a reusable fixture for
repetitive testing with charges up to 12 pounds TNT. This project was conducted
to meet client demands to test larger vehicle components without the need to
fabricate the full vehicle and to do so with larger charges.

Approach — SwRI had indications that a client would
pay for fixture fabrication if SwRI could design a fixture for full-scale
testing and demonstrate through numerical simulations that it could survive
repetitive testing with charges up to 60 pounds TNT. A quick-look project was
used to meet client needs for testing in the fourth quarter of 2013. The test
fixture needed weight and size goals to represent a full size vehicle, and
strength and durability were overriding concerns. Discussions with existing
clients led to a target size of 6 feet by 8 feet and a maximum weight of 32,000
pounds.

Accomplishments — CAD layouts were developed to size
the fixture to accommodate a 6-foot by 8-foot test article. Early layouts
indicated that the frame must be at least 7 foot by 9 foot in platform. If
fabricated from a solid plate, ballast could be cut from the plate center to
increase overall fixture weight. Although plates with thicknesses greater than
14 inches were considered for their bending strength and stiffness, a 14-inch
plate gave fixture weights that were consistent with the weight goals of the
project. A 14-inch thick, SA 516 Grade 70 steel plate, of adequate size, was
located in stock. Numerical simulations were performed to demonstrate that a
test fixture, cut from the SA 516 Grade 70 steel plate, was adequate to withstand
the blast loading from a buried 60-pound TNT charge. The final configuration is
shown below. It has been fabricated, and the first client-funded tests have been
performed with the fixture.

Southwest Research Institute® (SwRI®), headquartered in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied engineering and physical sciences research and development organization with
10 technical divisions.